Figure 7.

Structural characteristics of the I/V kissing-loop junction. (A) Minimized average structure showing the kissing-loop interaction. (B)(C) Base triples in the minimized average structure. Dashed lines represent the following hydrogen bonds defined on the basis of short distances in the ensemble of structures (given in parentheses): A14^V H61 and U8^V O2 (2.85–4.88 Å), A14^V N3 and C10^I H41 (2.57–3.43 Å), A14^V O2′ and C10^I N3 (3.06–4.56 Å), C7^I H41 and G14^I O6 (1.70–2.74 Å), C7^I N3 and G14^I H1 (2.85–4.52 Å in 19 structures). (D) Schematic representation of the kissing-loop interaction between SLIds2 and SLV. The arrows indicate intermolecular NOEs observed between residues at the kissing-loop junction (Table S2 of the Supporting Information). Residues shaded in orange form Watson–Crick base pairs at the kissing-loop junction, those shaded in green and purple are involved in base triples, and shaded gray boxes illustrate base stacking. For clarity, U13^V was drawn in a lighter green color.